////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 1996-2021 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
//
// Octave is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Octave is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Octave; see the file COPYING.  If not, see
// <https://www.gnu.org/licenses/>.
//
////////////////////////////////////////////////////////////////////////

#if ! defined (octave_pt_h)
#define octave_pt_h 1

#include "octave-config.h"

#include <string>

#include <iosfwd>

class octave_function;

namespace octave
{
  class tree_evaluator;
  class tree_walker;

  // Base class for the parse tree.

  class tree
  {
  public:

    tree (int l = -1, int c = -1)
      : m_line_num (l), m_column_num (c), m_bp_cond (nullptr)
    { }

    // No copying!

    tree (const tree&) = delete;

    tree& operator = (const tree&) = delete;

    virtual ~tree (void) = default;

    virtual int line (void) const { return m_line_num; }

    virtual int column (void) const { return m_column_num; }

    void line (int l) { m_line_num = l; }

    void column (int c) { m_column_num = c; }

    void set_location (int l, int c)
    {
      m_line_num = l;
      m_column_num = c;
    }

    virtual void set_breakpoint (const std::string& condition)
    {
      if (m_bp_cond)
        *m_bp_cond = condition;
      else
        m_bp_cond = new std::string (condition);
    }

    virtual void delete_breakpoint (void)
    {
      if (m_bp_cond)
        {
          delete m_bp_cond;

          m_bp_cond = nullptr;
        }
    }

    bool meets_bp_condition (tree_evaluator& tw) const;

    bool is_breakpoint (void) const
    {
      return m_bp_cond;
    }

    bool is_active_breakpoint (tree_evaluator& tw) const
    {
      return m_bp_cond && meets_bp_condition (tw);
    }

    // breakpoint condition, or "0" (i.e., "false") if no breakpoint.
    // To distinguish "0" from a disabled breakpoint, test "is_breakpoint" too.
    const std::string bp_cond (void) const
    {
      return m_bp_cond ? *m_bp_cond : "0";
    }

    std::string str_print_code (void);

    virtual void accept (tree_walker& tw) = 0;

  private:

    // The input line and column where we found the text that was
    // eventually converted to this tree node.
    int m_line_num;
    int m_column_num;

    // NULL if no breakpoint, or a breakpoint condition if there is one.
    std::string *m_bp_cond;
  };
}

#endif
